Vol. 54.] EAUJv^A OP THE SKIDDAW SLATES. 467 



paper. Mcholson's view, as there given — namely, that all the forms 

 from the Skiddaw Slates referred to the genus Mono grajjtus {Grapto- 

 lithus) were merely fragments of compound graptolites — is in accord 

 with the general opinion of geologists of the present day, the genus 

 Monograptus being wholly unknown in the Skiddaw Slates. His 

 hesitation in admitting the genus Dendrograptus has also been 

 justified by the fact that no true Dendrograptus is yet known from 

 these beds. Some of the forms referred to Dicliograptus in that 

 paper have since been made the types of new genera by Nicholson 

 or others, thus: — 



D'ichogra'p8us multiplex is now known as Temnograptus multiplex. 

 Dichograpsus retictclatus is now known as Schizograptus retimdatus. 

 Bichograpsus Logani is now known as Loganograptus Logani. 

 Dichograpsus antemiarius is now known as Cryptograptus antennarms. 



Again, Nicholson has subsequently erected one of the forms there 

 referred to Didgmograpsus cadiiceus, Salt., into a new species 

 D. gibberulus, and his D. serratulus (Hall) has become D. Micholsoni, 

 Lapw. 



Pinally, it is very probable that other forms referred to by him 

 are included in the present list under a different name. Thus : 



His Didgmograpsus sextans may be the Dicellograptus moffatensis 

 His Didgmograpsus geminus is the Didymograptus indentus 

 His Diplograpsus mucronatus may be the Cryptograptus HopTcin- 

 soni 



of the 

 present 

 paper. 



Since Nicholson wrote that paper, he has himself described several 

 new genera and species both in the Geol. Mag. and the Ann. & 

 Mag. Nat. Hist., and Lapworth has also added to the list. 



1894. In Geol. Mag. 1894, pp. 123-124, Marr gives the most 

 complete list that has hitherto appeared. He enumerates 46 

 species, belonging to 21 genera. Of these I reject both the 

 genera Janograptus and Ctenograptus, the former because I 

 think the determination was erroneous, and the latter because 

 I do not consider that the form in question is a graptolite at 

 all. I have also doubts as to the nature of Thamnograptus^ 

 but include it for the present. 



The species ' Teiragraptus fruticosus ' (Hall) I have never seen 

 in the Skiddaw Slates, though there are two species allied to it 

 occurring in the beds, with which I think it has been confused. I 

 am also inclined to think that large specimens of Didymograptus 

 hifidus (Hall) have been wrongly referred to D. Murchisoni (Boeck.), 

 and I consider that Dicliograptus SedgwicJcii, Salt., is identical with 

 D. octobrachiatus (Hall). This reduces Marr's list to 41 species, 

 belonging to 19 genera. To these I add 18 species and 3 genera, 

 bringing the total up to 59 species belonging to 22 genera; but 

 of these 7 species have never been previously recorded in this country 

 (they are indicated by an asterisk in the following list) and 7 are 

 new to science. The following are the genera and species of 

 graptolites at present known from the Skiddaw Slates : — 



